|
|
<!DOCTYPE HTML>
|
|
|
<html lang="en" class="light sidebar-visible" dir="ltr">
|
|
|
<head>
|
|
|
<!-- Book generated using mdBook -->
|
|
|
<meta charset="UTF-8">
|
|
|
<title>将模块拆分成多个文件 - Rust 程序设计语言 简体中文版</title>
|
|
|
|
|
|
|
|
|
<!-- Custom HTML head -->
|
|
|
|
|
|
<meta name="description" content="">
|
|
|
<meta name="viewport" content="width=device-width, initial-scale=1">
|
|
|
<meta name="theme-color" content="#ffffff">
|
|
|
|
|
|
<link rel="icon" href="favicon-de23e50b.svg">
|
|
|
<link rel="shortcut icon" href="favicon-8114d1fc.png">
|
|
|
<link rel="stylesheet" href="css/variables-8adf115d.css">
|
|
|
<link rel="stylesheet" href="css/general-2459343d.css">
|
|
|
<link rel="stylesheet" href="css/chrome-ae938929.css">
|
|
|
<link rel="stylesheet" href="css/print-9e4910d8.css" media="print">
|
|
|
|
|
|
<!-- Fonts -->
|
|
|
<link rel="stylesheet" href="fonts/fonts-9644e21d.css">
|
|
|
|
|
|
<!-- Highlight.js Stylesheets -->
|
|
|
<link rel="stylesheet" id="mdbook-highlight-css" href="highlight-493f70e1.css">
|
|
|
<link rel="stylesheet" id="mdbook-tomorrow-night-css" href="tomorrow-night-4c0ae647.css">
|
|
|
<link rel="stylesheet" id="mdbook-ayu-highlight-css" href="ayu-highlight-3fdfc3ac.css">
|
|
|
|
|
|
<!-- Custom theme stylesheets -->
|
|
|
<link rel="stylesheet" href="ferris-d33b75bf.css">
|
|
|
<link rel="stylesheet" href="theme/2018-edition-4e126c62.css">
|
|
|
<link rel="stylesheet" href="theme/semantic-notes-9b5766c0.css">
|
|
|
<link rel="stylesheet" href="theme/listing-cab26221.css">
|
|
|
|
|
|
|
|
|
<!-- Provide site root and default themes to javascript -->
|
|
|
<script>
|
|
|
const path_to_root = "";
|
|
|
const default_light_theme = "light";
|
|
|
const default_dark_theme = "navy";
|
|
|
window.path_to_searchindex_js = "searchindex-e0ffcbc3.js";
|
|
|
</script>
|
|
|
<!-- Start loading toc.js asap -->
|
|
|
<script src="toc-fb31ca2f.js"></script>
|
|
|
</head>
|
|
|
<body>
|
|
|
<div id="mdbook-help-container">
|
|
|
<div id="mdbook-help-popup">
|
|
|
<h2 class="mdbook-help-title">Keyboard shortcuts</h2>
|
|
|
<div>
|
|
|
<p>Press <kbd>←</kbd> or <kbd>→</kbd> to navigate between chapters</p>
|
|
|
<p>Press <kbd>S</kbd> or <kbd>/</kbd> to search in the book</p>
|
|
|
<p>Press <kbd>?</kbd> to show this help</p>
|
|
|
<p>Press <kbd>Esc</kbd> to hide this help</p>
|
|
|
</div>
|
|
|
</div>
|
|
|
</div>
|
|
|
<div id="mdbook-body-container">
|
|
|
<!-- Work around some values being stored in localStorage wrapped in quotes -->
|
|
|
<script>
|
|
|
try {
|
|
|
let theme = localStorage.getItem('mdbook-theme');
|
|
|
let sidebar = localStorage.getItem('mdbook-sidebar');
|
|
|
|
|
|
if (theme.startsWith('"') && theme.endsWith('"')) {
|
|
|
localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1));
|
|
|
}
|
|
|
|
|
|
if (sidebar.startsWith('"') && sidebar.endsWith('"')) {
|
|
|
localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1));
|
|
|
}
|
|
|
} catch (e) { }
|
|
|
</script>
|
|
|
|
|
|
<!-- Set the theme before any content is loaded, prevents flash -->
|
|
|
<script>
|
|
|
const default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? default_dark_theme : default_light_theme;
|
|
|
let theme;
|
|
|
try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
|
|
|
if (theme === null || theme === undefined) { theme = default_theme; }
|
|
|
const html = document.documentElement;
|
|
|
html.classList.remove('light')
|
|
|
html.classList.add(theme);
|
|
|
html.classList.add("js");
|
|
|
</script>
|
|
|
|
|
|
<input type="checkbox" id="mdbook-sidebar-toggle-anchor" class="hidden">
|
|
|
|
|
|
<!-- Hide / unhide sidebar before it is displayed -->
|
|
|
<script>
|
|
|
let sidebar = null;
|
|
|
const sidebar_toggle = document.getElementById("mdbook-sidebar-toggle-anchor");
|
|
|
if (document.body.clientWidth >= 1080) {
|
|
|
try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { }
|
|
|
sidebar = sidebar || 'visible';
|
|
|
} else {
|
|
|
sidebar = 'hidden';
|
|
|
sidebar_toggle.checked = false;
|
|
|
}
|
|
|
if (sidebar === 'visible') {
|
|
|
sidebar_toggle.checked = true;
|
|
|
} else {
|
|
|
html.classList.remove('sidebar-visible');
|
|
|
}
|
|
|
</script>
|
|
|
|
|
|
<nav id="mdbook-sidebar" class="sidebar" aria-label="Table of contents">
|
|
|
<!-- populated by js -->
|
|
|
<mdbook-sidebar-scrollbox class="sidebar-scrollbox"></mdbook-sidebar-scrollbox>
|
|
|
<noscript>
|
|
|
<iframe class="sidebar-iframe-outer" src="toc.html"></iframe>
|
|
|
</noscript>
|
|
|
<div id="mdbook-sidebar-resize-handle" class="sidebar-resize-handle">
|
|
|
<div class="sidebar-resize-indicator"></div>
|
|
|
</div>
|
|
|
</nav>
|
|
|
|
|
|
<div id="mdbook-page-wrapper" class="page-wrapper">
|
|
|
|
|
|
<div class="page">
|
|
|
<div id="mdbook-menu-bar-hover-placeholder"></div>
|
|
|
<div id="mdbook-menu-bar" class="menu-bar sticky">
|
|
|
<div class="left-buttons">
|
|
|
<label id="mdbook-sidebar-toggle" class="icon-button" for="mdbook-sidebar-toggle-anchor" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="mdbook-sidebar">
|
|
|
<span class=fa-svg><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!--! Font Awesome Free 6.2.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2022 Fonticons, Inc. --><path d="M0 96C0 78.3 14.3 64 32 64H416c17.7 0 32 14.3 32 32s-14.3 32-32 32H32C14.3 128 0 113.7 0 96zM0 256c0-17.7 14.3-32 32-32H416c17.7 0 32 14.3 32 32s-14.3 32-32 32H32c-17.7 0-32-14.3-32-32zM448 416c0 17.7-14.3 32-32 32H32c-17.7 0-32-14.3-32-32s14.3-32 32-32H416c17.7 0 32 14.3 32 32z"/></svg></span>
|
|
|
</label>
|
|
|
<button id="mdbook-theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme" aria-haspopup="true" aria-expanded="false" aria-controls="mdbook-theme-list">
|
|
|
<span class=fa-svg><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 576 512"><!--! Font Awesome Free 6.2.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2022 Fonticons, Inc. --><path d="M371.3 367.1c27.3-3.9 51.9-19.4 67.2-42.9L600.2 74.1c12.6-19.5 9.4-45.3-7.6-61.2S549.7-4.4 531.1 9.6L294.4 187.2c-24 18-38.2 46.1-38.4 76.1L371.3 367.1zm-19.6 25.4l-116-104.4C175.9 290.3 128 339.6 128 400c0 3.9 .2 7.8 .6 11.6c1.8 17.5-10.2 36.4-27.8 36.4H96c-17.7 0-32 14.3-32 32s14.3 32 32 32H240c61.9 0 112-50.1 112-112c0-2.5-.1-5-.2-7.5z"/></svg></span>
|
|
|
</button>
|
|
|
<ul id="mdbook-theme-list" class="theme-popup" aria-label="Themes" role="menu">
|
|
|
<li role="none"><button role="menuitem" class="theme" id="mdbook-theme-default_theme">Auto</button></li>
|
|
|
<li role="none"><button role="menuitem" class="theme" id="mdbook-theme-light">Light</button></li>
|
|
|
<li role="none"><button role="menuitem" class="theme" id="mdbook-theme-rust">Rust</button></li>
|
|
|
<li role="none"><button role="menuitem" class="theme" id="mdbook-theme-coal">Coal</button></li>
|
|
|
<li role="none"><button role="menuitem" class="theme" id="mdbook-theme-navy">Navy</button></li>
|
|
|
<li role="none"><button role="menuitem" class="theme" id="mdbook-theme-ayu">Ayu</button></li>
|
|
|
</ul>
|
|
|
<button id="mdbook-search-toggle" class="icon-button" type="button" title="Search (`/`)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="/ s" aria-controls="mdbook-searchbar">
|
|
|
<span class=fa-svg><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!--! Font Awesome Free 6.2.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2022 Fonticons, Inc. --><path d="M416 208c0 45.9-14.9 88.3-40 122.7L502.6 457.4c12.5 12.5 12.5 32.8 0 45.3s-32.8 12.5-45.3 0L330.7 376c-34.4 25.2-76.8 40-122.7 40C93.1 416 0 322.9 0 208S93.1 0 208 0S416 93.1 416 208zM208 352c79.5 0 144-64.5 144-144s-64.5-144-144-144S64 128.5 64 208s64.5 144 144 144z"/></svg></span>
|
|
|
</button>
|
|
|
</div>
|
|
|
|
|
|
<h1 class="menu-title">Rust 程序设计语言 简体中文版</h1>
|
|
|
|
|
|
<div class="right-buttons">
|
|
|
<a href="print.html" title="Print this book" aria-label="Print this book">
|
|
|
<span class=fa-svg id="print-button"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!--! Font Awesome Free 6.2.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2022 Fonticons, Inc. --><path d="M128 0C92.7 0 64 28.7 64 64v96h64V64H354.7L384 93.3V160h64V93.3c0-17-6.7-33.3-18.7-45.3L400 18.7C388 6.7 371.7 0 354.7 0H128zM384 352v32 64H128V384 368 352H384zm64 32h32c17.7 0 32-14.3 32-32V256c0-35.3-28.7-64-64-64H64c-35.3 0-64 28.7-64 64v96c0 17.7 14.3 32 32 32H64v64c0 35.3 28.7 64 64 64H384c35.3 0 64-28.7 64-64V384zm-16-88c-13.3 0-24-10.7-24-24s10.7-24 24-24s24 10.7 24 24s-10.7 24-24 24z"/></svg></span>
|
|
|
</a>
|
|
|
<a href="https://github.com/KaiserY/trpl-zh-cn/tree/main" title="Git repository" aria-label="Git repository">
|
|
|
<span class=fa-svg><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 496 512"><!--! Font Awesome Free 6.2.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2022 Fonticons, Inc. --><path d="M165.9 397.4c0 2-2.3 3.6-5.2 3.6-3.3.3-5.6-1.3-5.6-3.6 0-2 2.3-3.6 5.2-3.6 3-.3 5.6 1.3 5.6 3.6zm-31.1-4.5c-.7 2 1.3 4.3 4.3 4.9 2.6 1 5.6 0 6.2-2s-1.3-4.3-4.3-5.2c-2.6-.7-5.5.3-6.2 2.3zm44.2-1.7c-2.9.7-4.9 2.6-4.6 4.9.3 2 2.9 3.3 5.9 2.6 2.9-.7 4.9-2.6 4.6-4.6-.3-1.9-3-3.2-5.9-2.9zM244.8 8C106.1 8 0 113.3 0 252c0 110.9 69.8 205.8 169.5 239.2 12.8 2.3 17.3-5.6 17.3-12.1 0-6.2-.3-40.4-.3-61.4 0 0-70 15-84.7-29.8 0 0-11.4-29.1-27.8-36.6 0 0-22.9-15.7 1.6-15.4 0 0 24.9 2 38.6 25.8 21.9 38.6 58.6 27.5 72.9 20.9 2.3-16 8.8-27.1 16-33.7-55.9-6.2-112.3-14.3-112.3-110.5 0-27.5 7.6-41.3 23.6-58.9-2.6-6.5-11.1-33.3 2.6-67.9 20.9-6.5 69 27 69 27 20-5.6 41.5-8.5 62.8-8.5s42.8 2.9 62.8 8.5c0 0 48.1-33.6 69-27 13.7 34.7 5.2 61.4 2.6 67.9 16 17.7 25.8 31.5 25.8 58.9 0 96.5-58.9 104.2-114.8 110.5 9.2 7.9 17 22.9 17 46.4 0 33.7-.3 75.4-.3 83.6 0 6.5 4.6 14.4 17.3 12.1C428.2 457.8 496 362.9 496 252 496 113.3 383.5 8 244.8 8zM97.2 352.9c-1.3 1-1 3.3.7 5.2 1.6 1.6 3.9 2.3 5.2 1 1.3-1 1-3.3-.7-5.2-1.6-1.6-3.9-2.3-5.2-1zm-10.8-8.1c-.7 1.3.3 2.9 2.3 3.9 1.6 1 3.6.7 4.3-.7.7-1.3-.3-2.9-2.3-3.9-2-.6-3.6-.3-4.3.7zm32.4 35.6c-1.6 1.3-1 4.3 1.3 6.2 2.3 2.3 5.2 2.6 6.5 1 1.3-1.3.7-4.3-1.3-6.2-2.2-2.3-5.2-2.6-6.5-1zm-11.4-14.7c-1.6 1-1.6 3.6 0 5.9 1.6 2.3 4.3 3.3 5.6 2.3 1.6-1.3 1.6-3.9 0-6.2-1.4-2.3-4-3.3-5.6-2z"/></svg></span>
|
|
|
</a>
|
|
|
|
|
|
</div>
|
|
|
</div>
|
|
|
|
|
|
<div id="mdbook-search-wrapper" class="hidden">
|
|
|
<form id="mdbook-searchbar-outer" class="searchbar-outer">
|
|
|
<div class="search-wrapper">
|
|
|
<input type="search" id="mdbook-searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="mdbook-searchresults-outer" aria-describedby="searchresults-header">
|
|
|
<div class="spinner-wrapper">
|
|
|
<span class=fa-svg id="fa-spin"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!--! Font Awesome Free 6.2.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2022 Fonticons, Inc. --><path d="M304 48c0-26.5-21.5-48-48-48s-48 21.5-48 48s21.5 48 48 48s48-21.5 48-48zm0 416c0-26.5-21.5-48-48-48s-48 21.5-48 48s21.5 48 48 48s48-21.5 48-48zM48 304c26.5 0 48-21.5 48-48s-21.5-48-48-48s-48 21.5-48 48s21.5 48 48 48zm464-48c0-26.5-21.5-48-48-48s-48 21.5-48 48s21.5 48 48 48s48-21.5 48-48zM142.9 437c18.7-18.7 18.7-49.1 0-67.9s-49.1-18.7-67.9 0s-18.7 49.1 0 67.9s49.1 18.7 67.9 0zm0-294.2c18.7-18.7 18.7-49.1 0-67.9S93.7 56.2 75 75s-18.7 49.1 0 67.9s49.1 18.7 67.9 0zM369.1 437c18.7 18.7 49.1 18.7 67.9 0s18.7-49.1 0-67.9s-49.1-18.7-67.9 0s-18.7 49.1 0 67.9z"/></svg></span>
|
|
|
</div>
|
|
|
</div>
|
|
|
</form>
|
|
|
<div id="mdbook-searchresults-outer" class="searchresults-outer hidden">
|
|
|
<div id="mdbook-searchresults-header" class="searchresults-header"></div>
|
|
|
<ul id="mdbook-searchresults">
|
|
|
</ul>
|
|
|
</div>
|
|
|
</div>
|
|
|
|
|
|
<!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM -->
|
|
|
<script>
|
|
|
document.getElementById('mdbook-sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible');
|
|
|
document.getElementById('mdbook-sidebar').setAttribute('aria-hidden', sidebar !== 'visible');
|
|
|
Array.from(document.querySelectorAll('#mdbook-sidebar a')).forEach(function(link) {
|
|
|
link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1);
|
|
|
});
|
|
|
</script>
|
|
|
|
|
|
<div id="mdbook-content" class="content">
|
|
|
<main>
|
|
|
<h2 id="将模块拆分成多个文件"><a class="header" href="#将模块拆分成多个文件">将模块拆分成多个文件</a></h2>
|
|
|
<p><a href="https://github.com/rust-lang/book/blob/79b9d15410a7b15a65cb86bcb40cbea99198a9e4/src/ch07-05-separating-modules-into-different-files.md">ch07-05-separating-modules-into-different-files.md</a></p>
|
|
|
<p>到目前为止，本章的所有示例都在一个文件中定义了多个模块。当模块变大时，你可能想把它们的定义移到单独的文件中，以便让代码更容易浏览。</p>
|
|
|
<p>例如，我们从示例 7-17 中包含多个餐厅模块的代码开始。我们会将模块提取到各自的文件中，而不是将所有模块都定义到 crate 根文件中。在这里，crate 根文件是 <em>src/lib.rs</em>，不过这个过程也适用于 crate 根文件是 <em>src/main.rs</em> 的二进制 crate。</p>
|
|
|
<p>首先把 <code>front_of_house</code> 模块提取到它自己的文件中。删除 <code>front_of_house</code> 模块花括号内的代码，只保留 <code>mod front_of_house;</code> 声明，这样 <em>src/lib.rs</em> 就会只剩下示例 7-21 所示的代码。注意，在创建出示例 7-22 中的 <em>src/front_of_house.rs</em> 文件之前，这段代码都无法编译。</p>
|
|
|
<p><span class="filename">文件名：src/lib.rs</span></p>
|
|
|
<pre><code class="language-rust ignore does_not_compile">mod front_of_house;
|
|
|
|
|
|
pub use crate::front_of_house::hosting;
|
|
|
|
|
|
pub fn eat_at_restaurant() {
|
|
|
hosting::add_to_waitlist();
|
|
|
}</code></pre>
|
|
|
<p><span class="caption">示例 7-21: 声明 <code>front_of_house</code> 模块，其内容将位于 <em>src/front_of_house.rs</em></span></p>
|
|
|
<p>接下来，把刚才花括号中的代码放进一个名为 <em>src/front_of_house.rs</em> 的新文件中，如示例 7-22 所示。编译器之所以知道要去这个文件里查找，是因为它在 crate 根中看到了名为 <code>front_of_house</code> 的模块声明。</p>
|
|
|
<p><span class="filename">文件名：src/front_of_house.rs</span></p>
|
|
|
<pre><code class="language-rust ignore">pub mod hosting {
|
|
|
pub fn add_to_waitlist() {}
|
|
|
}</code></pre>
|
|
|
<p><span class="caption">示例 7-22: 在 <em>src/front_of_house.rs</em> 中定义 <code>front_of_house</code> 模块</span></p>
|
|
|
<p>注意，在模块树中，你只需要用 <code>mod</code> 声明加载某个文件一次。一旦编译器知道这个文件是项目的一部分了，并且因为 <code>mod</code> 语句所在的位置而知道这段代码位于模块树的什么位置，那么项目中的其他文件就应该用它声明位置对应的路径来引用这段代码，这一点会在<a href="ch07-03-paths-for-referring-to-an-item-in-the-module-tree.html">“引用模块树中项的路径”</a>部分讲到。换句话说，<code>mod</code> <strong>不是</strong>某些其他编程语言里那种 “include” 操作。</p>
|
|
|
<p>接下来，我们也把 <code>hosting</code> 模块提取到它自己的文件中。这个过程稍有不同，因为 <code>hosting</code> 是 <code>front_of_house</code> 的子模块，而不是根模块。我们会把 <code>hosting</code> 对应的文件放进一个以其在模块树中的祖先模块命名的新目录中，这里就是 <em>src/front_of_house</em>。</p>
|
|
|
<p>要开始移动 <code>hosting</code>，先把 <em>src/front_of_house.rs</em> 改成只包含 <code>hosting</code> 模块的声明：</p>
|
|
|
<p><span class="filename">文件名：src/front_of_house.rs</span></p>
|
|
|
<pre><code class="language-rust ignore">pub mod hosting;</code></pre>
|
|
|
<p>然后，创建一个 <em>src/front_of_house</em> 目录和一个 <em>hosting.rs</em> 文件，用来放置 <code>hosting</code> 模块中的定义：</p>
|
|
|
<p><span class="filename">文件名：src/front_of_house/hosting.rs</span></p>
|
|
|
<pre><code class="language-rust ignore">pub fn add_to_waitlist() {}</code></pre>
|
|
|
<p>如果我们反而把 <em>hosting.rs</em> 放在 <em>src</em> 目录中，编译器就会认为 <em>hosting.rs</em> 里的代码属于在 crate 根中声明的 <code>hosting</code> 模块，而不是 <code>front_of_house</code> 的子模块。编译器关于“要去哪些文件中查找哪些模块代码”的规则，使得目录和文件结构会更贴近模块树本身。</p>
|
|
|
<blockquote>
|
|
|
<h3 id="替代文件路径"><a class="header" href="#替代文件路径">替代文件路径</a></h3>
|
|
|
<p>到目前为止，我们介绍的是 Rust 编译器最惯用的文件路径，不过 Rust 也支持一种较旧的文件路径风格。</p>
|
|
|
<p>对于在 crate 根中声明的 <code>front_of_house</code> 模块，编译器会在以下位置查找模块代码：</p>
|
|
|
<ul>
|
|
|
<li><em>src/front_of_house.rs</em>（前面介绍的方式）</li>
|
|
|
<li><em>src/front_of_house/mod.rs</em>（较旧的风格，但仍然受支持）</li>
|
|
|
</ul>
|
|
|
<p>对于 <code>front_of_house</code> 的子模块 <code>hosting</code>，编译器会在以下位置查找模块代码：</p>
|
|
|
<ul>
|
|
|
<li><em>src/front_of_house/hosting.rs</em>（前面介绍的方式）</li>
|
|
|
<li><em>src/front_of_house/hosting/mod.rs</em>（较旧的风格，但仍然受支持）</li>
|
|
|
</ul>
|
|
|
<p>如果你对同一个模块同时使用这两种风格，编译器就会报错。在同一个项目里为不同模块混用两种风格是允许的，不过这可能会让浏览项目的人感到困惑。</p>
|
|
|
<p>使用 <em>mod.rs</em> 这种文件名风格的主要缺点是，项目里最后可能会有很多都叫 <em>mod.rs</em> 的文件；当你在编辑器里同时打开它们时，就会变得很混乱。</p>
|
|
|
</blockquote>
|
|
|
<p>现在，我们已经把每个模块的代码都移动到了独立文件中，而模块树保持不变。<code>eat_at_restaurant</code> 中的函数调用也完全不需要修改，即使这些定义现在位于不同的文件中也一样能工作。这个技巧让你可以在模块逐渐变大时，再把它们迁移到新文件里。</p>
|
|
|
<p>注意，<em>src/lib.rs</em> 中的 <code>pub use crate::front_of_house::hosting</code> 语句也完全没有变化，而且 <code>use</code> 也不会影响 crate 会编译哪些文件。<code>mod</code> 关键字用来声明模块，而 Rust 会在与模块同名的文件中查找应放进该模块的代码。</p>
|
|
|
<h2 id="总结"><a class="header" href="#总结">总结</a></h2>
|
|
|
<p>Rust 允许你把一个包拆分成多个 crate，再把一个 crate 拆分成多个模块，这样你就能在一个模块中引用另一个模块里定义的项。你既可以使用绝对路径，也可以使用相对路径。还可以用 <code>use</code> 语句把路径引入作用域，这样在同一作用域内多次使用该项时就能写更短的路径。模块代码默认是私有的，不过你可以加上 <code>pub</code> 关键字，把定义公开出去。</p>
|
|
|
<p>下一章，我们将看看标准库中的一些集合数据结构，你可以在组织良好的代码中使用它们。</p>
|
|
|
|
|
|
</main>
|
|
|
|
|
|
<nav class="nav-wrapper" aria-label="Page navigation">
|
|
|
<!-- Mobile navigation buttons -->
|
|
|
<a rel="prev" href="ch07-04-bringing-paths-into-scope-with-the-use-keyword.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
|
|
|
<span class=fa-svg><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!--! Font Awesome Free 6.2.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2022 Fonticons, Inc. --><path d="M41.4 233.4c-12.5 12.5-12.5 32.8 0 45.3l160 160c12.5 12.5 32.8 12.5 45.3 0s12.5-32.8 0-45.3L109.3 256 246.6 118.6c12.5-12.5 12.5-32.8 0-45.3s-32.8-12.5-45.3 0l-160 160z"/></svg></span>
|
|
|
</a>
|
|
|
|
|
|
<a rel="next prefetch" href="ch08-00-common-collections.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
|
|
|
<span class=fa-svg><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!--! Font Awesome Free 6.2.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2022 Fonticons, Inc. --><path d="M278.6 233.4c12.5 12.5 12.5 32.8 0 45.3l-160 160c-12.5 12.5-32.8 12.5-45.3 0s-12.5-32.8 0-45.3L210.7 256 73.4 118.6c-12.5-12.5-12.5-32.8 0-45.3s32.8-12.5 45.3 0l160 160z"/></svg></span>
|
|
|
</a>
|
|
|
|
|
|
<div style="clear: both"></div>
|
|
|
</nav>
|
|
|
</div>
|
|
|
</div>
|
|
|
|
|
|
<nav class="nav-wide-wrapper" aria-label="Page navigation">
|
|
|
<a rel="prev" href="ch07-04-bringing-paths-into-scope-with-the-use-keyword.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
|
|
|
<span class=fa-svg><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!--! Font Awesome Free 6.2.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2022 Fonticons, Inc. --><path d="M41.4 233.4c-12.5 12.5-12.5 32.8 0 45.3l160 160c12.5 12.5 32.8 12.5 45.3 0s12.5-32.8 0-45.3L109.3 256 246.6 118.6c12.5-12.5 12.5-32.8 0-45.3s-32.8-12.5-45.3 0l-160 160z"/></svg></span>
|
|
|
</a>
|
|
|
|
|
|
<a rel="next prefetch" href="ch08-00-common-collections.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
|
|
|
<span class=fa-svg><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 320 512"><!--! Font Awesome Free 6.2.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2022 Fonticons, Inc. --><path d="M278.6 233.4c12.5 12.5 12.5 32.8 0 45.3l-160 160c-12.5 12.5-32.8 12.5-45.3 0s-12.5-32.8 0-45.3L210.7 256 73.4 118.6c-12.5-12.5-12.5-32.8 0-45.3s32.8-12.5 45.3 0l160 160z"/></svg></span>
|
|
|
</a>
|
|
|
</nav>
|
|
|
|
|
|
</div>
|
|
|
|
|
|
<template id=fa-eye><span class=fa-svg><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 576 512"><!--! Font Awesome Free 6.2.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2022 Fonticons, Inc. --><path d="M288 32c-80.8 0-145.5 36.8-192.6 80.6C48.6 156 17.3 208 2.5 243.7c-3.3 7.9-3.3 16.7 0 24.6C17.3 304 48.6 356 95.4 399.4C142.5 443.2 207.2 480 288 480s145.5-36.8 192.6-80.6c46.8-43.5 78.1-95.4 93-131.1c3.3-7.9 3.3-16.7 0-24.6c-14.9-35.7-46.2-87.7-93-131.1C433.5 68.8 368.8 32 288 32zM432 256c0 79.5-64.5 144-144 144s-144-64.5-144-144s64.5-144 144-144s144 64.5 144 144zM288 192c0 35.3-28.7 64-64 64c-11.5 0-22.3-3-31.6-8.4c-.2 2.8-.4 5.5-.4 8.4c0 53 43 96 96 96s96-43 96-96s-43-96-96-96c-2.8 0-5.6 .1-8.4 .4c5.3 9.3 8.4 20.1 8.4 31.6z"/></svg></span></template>
|
|
|
<template id=fa-eye-slash><span class=fa-svg><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 640 512"><!--! Font Awesome Free 6.2.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2022 Fonticons, Inc. --><path d="M38.8 5.1C28.4-3.1 13.3-1.2 5.1 9.2S-1.2 34.7 9.2 42.9l592 464c10.4 8.2 25.5 6.3 33.7-4.1s6.3-25.5-4.1-33.7L525.6 386.7c39.6-40.6 66.4-86.1 79.9-118.4c3.3-7.9 3.3-16.7 0-24.6c-14.9-35.7-46.2-87.7-93-131.1C465.5 68.8 400.8 32 320 32c-68.2 0-125 26.3-169.3 60.8L38.8 5.1zM223.1 149.5C248.6 126.2 282.7 112 320 112c79.5 0 144 64.5 144 144c0 24.9-6.3 48.3-17.4 68.7L408 294.5c5.2-11.8 8-24.8 8-38.5c0-53-43-96-96-96c-2.8 0-5.6 .1-8.4 .4c5.3 9.3 8.4 20.1 8.4 31.6c0 10.2-2.4 19.8-6.6 28.3l-90.3-70.8zm223.1 298L373 389.9c-16.4 6.5-34.3 10.1-53 10.1c-79.5 0-144-64.5-144-144c0-6.9 .5-13.6 1.4-20.2L83.1 161.5C60.3 191.2 44 220.8 34.5 243.7c-3.3 7.9-3.3 16.7 0 24.6c14.9 35.7 46.2 87.7 93 131.1C174.5 443.2 239.2 480 320 480c47.8 0 89.9-12.9 126.2-32.5z"/></svg></span></template>
|
|
|
<template id=fa-copy><span class=fa-svg><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!--! Font Awesome Free 6.2.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2022 Fonticons, Inc. --><path d="M502.6 70.63l-61.25-61.25C435.4 3.371 427.2 0 418.7 0H255.1c-35.35 0-64 28.66-64 64l.0195 256C192 355.4 220.7 384 256 384h192c35.2 0 64-28.8 64-64V93.25C512 84.77 508.6 76.63 502.6 70.63zM464 320c0 8.836-7.164 16-16 16H255.1c-8.838 0-16-7.164-16-16L239.1 64.13c0-8.836 7.164-16 16-16h128L384 96c0 17.67 14.33 32 32 32h47.1V320zM272 448c0 8.836-7.164 16-16 16H63.1c-8.838 0-16-7.164-16-16L47.98 192.1c0-8.836 7.164-16 16-16H160V128H63.99c-35.35 0-64 28.65-64 64l.0098 256C.002 483.3 28.66 512 64 512h192c35.2 0 64-28.8 64-64v-32h-47.1L272 448z"/></svg></span></template>
|
|
|
<template id=fa-play><span class=fa-svg><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 384 512"><!--! Font Awesome Free 6.2.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2022 Fonticons, Inc. --><path d="M73 39c-14.8-9.1-33.4-9.4-48.5-.9S0 62.6 0 80V432c0 17.4 9.4 33.4 24.5 41.9s33.7 8.1 48.5-.9L361 297c14.3-8.7 23-24.2 23-41s-8.7-32.2-23-41L73 39z"/></svg></span></template>
|
|
|
<template id=fa-clock-rotate-left><span class=fa-svg><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!--! Font Awesome Free 6.2.0 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2022 Fonticons, Inc. --><path d="M75 75L41 41C25.9 25.9 0 36.6 0 57.9V168c0 13.3 10.7 24 24 24H134.1c21.4 0 32.1-25.9 17-41l-30.8-30.8C155 85.5 203 64 256 64c106 0 192 86 192 192s-86 192-192 192c-40.8 0-78.6-12.7-109.7-34.4c-14.5-10.1-34.4-6.6-44.6 7.9s-6.6 34.4 7.9 44.6C151.2 495 201.7 512 256 512c141.4 0 256-114.6 256-256S397.4 0 256 0C185.3 0 121.3 28.7 75 75zm181 53c-13.3 0-24 10.7-24 24V256c0 6.4 2.5 12.5 7 17l72 72c9.4 9.4 24.6 9.4 33.9 0s9.4-24.6 0-33.9l-65-65V152c0-13.3-10.7-24-24-24z"/></svg></span></template>
|
|
|
|
|
|
|
|
|
|
|
|
<script>
|
|
|
window.playground_copyable = true;
|
|
|
</script>
|
|
|
|
|
|
|
|
|
<script src="elasticlunr-ef4e11c1.min.js"></script>
|
|
|
<script src="mark-09e88c2c.min.js"></script>
|
|
|
<script src="searcher-c2a407aa.js"></script>
|
|
|
|
|
|
<script src="clipboard-1626706a.min.js"></script>
|
|
|
<script src="highlight-abc7f01d.js"></script>
|
|
|
<script src="book-a0b12cfe.js"></script>
|
|
|
|
|
|
<!-- Custom JS scripts -->
|
|
|
<script src="ferris-2317480c.js"></script>
|
|
|
|
|
|
|
|
|
|
|
|
</div>
|
|
|
</body>
|
|
|
</html>
|
